In this case when the user click in the image, this images is showed with 100% of the browser height, and the user can go to the next/previous image. When the user clicks again the image is showed in a bigger size(may be in the real size) and the user can go up and down in the image, but with out scroll, just moving the mouse.

What I want to do is when the user click the first time in the image go right to the last step: The biggest image with up and down synchronized with the mouse movement, and the possibility to go to the next image. In other words a mix with the features of the first and the second step of the original case.

Which will resize the image if the user decides to resize your window, this way it's always taking up the full height of your browser.

With #2, the arrows just create a new img tag. And the idea is something like

function loadnew() {
// create the new image
var newimg = "<img id='newimg'></img>"
$("#imgcontainer").append(newimg);
// make sure it has the same classes as the current img
// so that it's in the same position with an higher z-index
// then load the image
$("#newimg").addClass( "class1 class2" );
$("#newimg").css( "z-index", "+=1" );
$("#newimg").css( "opacity", 0 );
$("#newimg").attr("src", "url/to/img");
// animate the thing and then replace the src of the old one with this new one
$("#newimg").animate( {
opacity: 1;
}, 1000, function() {
$(oldimg).attr("src", $("#newimg").attr("src"));
});
}

Now with #3, you will size the image with respect to the width. The div fixed positioned. So again, you need a